At 9:05 PM 10/31/96, Charles F. Goldfarb wrote:
>But in SGML they are always accessed and parsed, and the resulting ESIS is
>always the same. (Yes, I know that 8879 doesn't mention ESIS by name, but the
>SGML conformance testing standard certainly does.)
Yes, but we are not proposing that XML be SGML conformant, just that an
SGML-comformant processor be able to parse XML.
>Lazy parsing needn't be inconsistent with 8879 conformance, as early postings
>have demonstrated, as long as the external text entity doesn't change the state
>of the parse. (I still question whether XML can enforce this constraint.)
Well, given the work that Steve DeRose and others in SGML OPEN expended on
finding all the state-dependencies in the SGML grammar, I believe him when
he says we _already have_ guaranteed that. Or do you have a context
dependency in mind tath we have not already eliminated.
>The real problem is with entities whose text changes each time they are
>accessed, thereby yielding a different ESIS on each parse. Valid XML should
>require that external text entities be constants. Generated files should be
>accessed through attributes, where there is a chance to identify the governing
>semantics of the reference.
I'm afraid the only thing I can say is that this would be a stupid
restriction: it is not enforceable by any processor, _and_ it would make
impossible many useful applications of XML on the Web, that will
necessarily involve databases and synamic document generation. It is the
responsibility of a dynamic document implementor to produce valid XML, if
they want to validate it.
What is the point of trying to make a rule that is easy to violate, blocks
useful applications of XML, and cannot be enforced by software?
-- David
RE delenda est.
I am not a number. I am an undefined character.
_________________________________________
David Durand dgd@cs.bu.edu \ david@dynamicDiagrams.com
Boston University Computer Science \ Sr. Analyst
http://www.cs.bu.edu/students/grads/dgd/ \ Dynamic Diagrams
--------------------------------------------\ http://dynamicDiagrams.com/
MAPA: mapping for the WWW \__________________________